People walk past army soldiers guarding in front of the Egyptian museum in Tahrir square, in Cairo, August 19. Suspected Islamist militants killed 25 Egyptian policemen on Monday in the Sinai peninsula, where attacks on security forces have multiplied since the army overthrew President Mohamed Morsi on July 3.

Jerusalem — The Sinai militant attack that killed 25 Egyptian policemen today underscores the stakes as both sides battle for this strategic foothold in the Middle East. The attack reportedly took place near Rafah, with militants ambushing two minibuses carrying Egyptian policemen. It is one of the worst since former president Hosni Mubarak was ousted in February 2011 and echoes a brazen attack in the same area that killed 16 Egyptian policemen a year ago.

While details of today’s attack are still emerging, the overall challenge is abundantly clear. An uptick in militant attacks in Sinai since the military deposed President Mohamed Morsi on July 3 places additional strain on security forces already preoccupied with escalating political violence in Cairo and elsewhere, and has raised concerns that Sinai is on the road to becoming a magnet for global jihadi groups.

In addition, some worry that after Islamists saw their democratically elected president ousted by the Egyptian military and their Cairo sit-ins dispersed with gunfire, killing more than 600 people in the past week, they will turn to violence.

"The army coup and crackdown will drive thousands of Egyptian Islamists to Al Qaeda in the Sinai and elsewhere," said Bruce Riedel, a fellow at the Brookings Institute in Washington and veteran of the CIA, in an e-mail. "The army has validated Al Qaeda's narrative, elections are a false path to change. The only answer is jihad."

Last month, the Egyptian military sent two additional brigades into Egypt to crack down on militant groups who, sometimes in concert with aggrieved Bedouin locals, have targeted both Egyptian security forces and Israel. Some of the most brazen attacks, including the one at Rafah in August 2012, were carried out by Ansar Bayt al-Maqdis (also known as Ansar Jerusalem).

The group is not an affiliate of Al Qaeda, such as Al Qaeda in the Arabian Peninsula (AQAP), but it is considered an ally – albeit a small one, says Seth Jones, a terrorist analyst at the RAND Corp.

As early as 2011, flyers appeared in the Sinai promoting Al Qaeda in the Sinai peninsula, and at least some of the dozen or more militant groups appear to have followed the model, if not direct instructions, from the original Al Qaeda in Pakistan. Some foreigners have been among the militants killed or captured in the past two years, fueling concerns that Sinai could attract global jihadis from Syria, Yemen, or elsewhere.

Since the Egyptian military ousted Mr. Morsi, Al Qaeda affiliates have called for the overthrow of the Egyptian government, says Mr. Jones, author of "Hunting in the Shadows: The Pursuit of al Qa'ida since 9/11." Among them have been Al Qaeda groups in Yemen (AQAP), Somalia (Al Shabaab), North Africa (Al Qaeda in the Maghreb), and Syria (Jusrat al-Nusra).

Many Egyptians, however, say the Muslim Brotherhood and its followers are behind the violence in Sinai, ostensibly as a way to undermine the interim government that was installed by the military. The organization has firmly denied any involvement in the violence, but Islamist leaders have said that it could be difficult to control their followers.

"The problem is that we intend on staying peaceful, and the Brotherhood intends on staying peaceful, but we can’t control everyone, especially young people,” said Ahmed Hosny, spokesman for Al Gamaa al-Islamiyya, a former militant group, in an interview earlier this month. The group split from the Muslim Brotherhood but later renounced violence in order to work its way into the political process.

"There may come a day when those people feel like we are weak leaders, we are not confronting [the state ... and they may decide to split from us,” he added, noting that that was what happened with the Brotherhood in the 1960s. “What kind of violence they will do – we can’t control that."

That could increase the strain on the Egyptian government's resources and make it increasingly difficult to crack down on violence in the Sinai, says Jones of RAND.

"Since the Arab uprising started and Egypt was caught up in that, the Egyptian security apparatus has had to focus a lot more on internal threats to the state and stabilizing the government, and has pulled resources and assets out of the Sinai," he says. "The really serious problem for the Egyptian military is if the struggle with the Muslim Brotherhood and the levels of violence increase in Egypt, the security forces are going to have to respond to larger demonstrations.... That pulls resources away from other areas and makes it hard to put resources in the Sinai."